The present invention relates to a system for disposing of infectious, biologically contaminated waste material. More particularly, the present invention relates to a device for shredding, disintegrating, and disinfecting biologically contaminated waste products.
Examples of biologically contaminated waste products include hypodermic syringes, glassware, slides, gauze, needles, infectious tissues, blood-soaked materials, or other such potentially infected or contaminated waste materials typically generated during normal operation of a hospital. Public concern over the proper treatment and disposal of medical waste products has increased over the past several years. This increase is due in part to an increased public awareness of the diseases that can be transmitted by biologically contaminated waste products. It is therefore desirable to produce a disposal system which adequately disinfects and destroys medical waste products while minimizing the amount of contact between the medical waste products and an operator of the disposal system.
Various types of systems are known for disposing of medical waste products. On-site incinerators have been used in the past to dispose of such dangerous and infectious medical waste products. Incinerators which may be effective in decontaminating and reducing the size of the medical waste materials are not fully satisfactory because they require regular servicing and cleaning and provide some danger of toxic gas emissions. In recent years, systems have been developed to dispose of medical waste products without the use of such incinerators or other thermal devices.
It is known to provide devices which disintegrate medical waste products while mixing the waste products with liquid disinfectant solutions to produce a non-infectious and safely disposable particulate residue. One such known device provides a rotary hammermill which disintegrates medical waste products into a particulate form in the presence of a disinfectant. The solid particulate waste is then separated from the disinfectant solution by a suitable liquid-solid particle separator. Examples of such medical waste disposal systems are shown in U.S. Pat. Nos. 4,578,185; 4,618,103; and 4,619,409.
Problems still exist with these known nonthermal disposal systems. Even though these known systems effectively disinfect and destroy medical waste, operators of the systems still have substantial contact with medical waste products. Medical waste products generated by hospitals are typically stored inside rigid, self-supporting, form-stable containers. These containers are often made of a nonbreakable plastic material, but they may be made from any suitable material. The containers come in various shapes and sizes. The containers prevent leakage of fluids from inside the containers, and the rigid walls of the containers prevent needles, broken glass, or other articles from penetrating the container to isolate these medical waste products from hospital personnel. The containers typically have sealed lids to cover an opening of the container to prevent contact between hospital personnel and the medical waste products inside the containers.
To dispose of the medical waste products in the containers, an operator must typically dump the contents of the containers into the disposal system for processing. By removing the medical waste products from the containers, the operator is exposed to the infectious, contaminated medical waste material. This exposure increases the risk that the operator will be cut by glass products or punctured by syringe needles inside the container. The glass and needles inside the container are often covered with blood or other potentially harmful materials. Therefore, there is a risk that the operator may be infected by the contaminated medical waste products inside the container when disposing of the products by conventional methods.
One object of the present invention is to minimize the amount of contact between hospital personnel and biologically contaminated medical waste products produced by the hospital.
Another object of the present invention is to provide a disposal system for disinfecting and disposing of the entire contents of a rigid, self-supporting, form-stable container containing biologically contaminated waste products without requiring removal of the waste products from the container thereby preventing exposure of an operator of the disposal system to the potentially dangerous medical waste products.
Yet another object of the present invention is to dispose of the entire contents of a waste-filled container without the use of thermal processes.
According to the present invention, a waste disposal system for disposing of biologically contaminated waste material situated inside a self-supporting, form-stable container is provided. The system includes means for processing the entire container including an input for receiving the container, means for shredding the container and the waste material therein to form a shredded mass, and an output for discharging the shredded mass from the processing means. The shredding means feeds the shredded mass through the output of the processing means. The waste disposal system also includes means for disintegrating the shredded mass into a particulate waste material. The disintegrating means includes an input coupled to the output of the processing means for receiving the shredded mass from the output of the processing means.
In a preferred embodiment of the present invention, the processing means includes a trough portion formed to include an input for receiving the waste-filled container and an output aperture for discharging the shredded mass from the trough portion. The processing means includes a rotatable auger screw having a proximal end, a distal end, and an axis of rotation. The auger screw is situated inside the trough portion for shredding the waste-filled container into the shredded mass and for transporting the shredded mass in a direction along the axis of rotation toward the output aperture of the trough portion to discharge the shredded mass from the trough portion. The processing means also includes means coupled to the proximal end of the auger screw for rotating the auger screw in a predetermined direction about its axis of rotation.
Hopper means is provided for defining an enclosed housing coupled to the input of the trough portion. The hopper means includes input means for receiving the container inside the enclosed housing. The processing means further includes ram means situated inside the hopper means for applying a biasing force to the container to force the container against the auger screw and to retain the container in engagement with the auger screw until the auger screw shreds the entire container into the shredded mass.
The hopper means includes a door for covering the input means movable between an open position to permit the container to be loaded into the hopper means and a closed position for sealing the input means after the container is positioned within the hopper means. The processing means further includes means for disabling the ram means and the rotating means when the door is in the open position to prevent an operator from being injured by either the ram means or the rotating auger screw.
In one preferred embodiment, the ram means includes a plunger situated inside the hopper means for engaging the container and means interconnecting the plunger and the hopper means for providing reciprocating movement of the plunger from a first position to permit the container to be loaded into the hopper means and a second position to force the container into engagement with the auger screw to shred the container. The reciprocating means can include a pneumatically controlled air cylinder situated inside the hopper means. The air cylinder is movable from a retracted position defining the first position of the plunger to an extended position defining the second position of the plunger.
The processing means can also include means for providing a liquid disinfectant solution to the trough portion to clean the auger screw and to treat the shredded mass with the liquid disinfectant solution. Exhaust means coupled to the hopper means can also be included for providing a negative pressure inside the hopper means during operation of the auger screw to vent the hopper means and the trough portion of the system while shredding the container. The exhaust means prevents contaminated air from escaping from within the hopper means into the surrounding atmosphere while shredding the container. The exhaust can be filtered to remove contaminants from the exhaust.
The processing means can also include a gate region between the trough portion and the hammermill which includes a reciprocating plate member for opening and closing the gate region. When the door to the hopper is open, plate member blocks the gate region to prevent small particles escaping from the hammermill from passing upwardly through the trough portion and through the opening in the hopper.
A system computer is used to synchronize and control the means for rotating the auger screw, the ram means, the exhaust means, the supply of disinfectant solution to the trough portion, and the movement of the plate member.
One feature of the present invention is the provision of a processing unit including an auger screw for shredding a container filled with waste material into a shredded mass and for feeding the shredded mass into a disintegrator for disintegrating the shredded mass into a particulate waste product. Advantageously, such a feature permits an entire rigid, form-stable container to be processed and sanitized without removing biologically contaminated waste material from the container to prevent contact between the contaminated waste material and an operator of the disposal device. This feature reduces the risk of injury to the operator and reduces the risk of exposing the operator to the infectious contaminated medical waste products situated inside the containers.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.